Water as an Internal Reference for Spectroscopic Imaging: Methodology, Application, and Comparison to Other Methods

The unsuppressed 'internal' water signal was introduced as a concentration reference for single-voxel proton magnetic resonance spectroscopy (1H-MRS) of the brain over a decade ago (1). However, to our knowledge, a detailed description of how this method could be applied to spectroscopic imaging (SI) or an examination of its potential sources of error has yet to be reported. Here we describe a method for using water as concentration reference in SI and its application to a study on gray matter (GM) and white matter (WM) metabolite concentrations in healthy adult subjects.